1. Field of the Invention
The present invention is generally related to cooking appliances, and more particularly to an improved stove of ornament and gas saving in cooking.
2. Description of the Prior Art
In general gas stoves are well known. The following 13 United States patents and published patent applications are the closest prior art references which are related to the present invention.
U.S. Pat. No. 1,156,087 issued to Kupfer on Oct. 12, 1915 for “Flame Shield For Gas Stove” discloses a cylindrical metal tube which is used as a flame shield for a burner of a gas stove. The flame shield is positioned between the stove grids on the cooktop and a platform placed under the cooktop, wherein an upper end of the shield reaches into the plane of the undersurface of the grids, a lower end of the shield rests upon the platform, and the body of the shield surrounds the burner.
U.S. Pat. No. 2,166,442 issued to Kahn on Jul. 18, 1939 for “Cooking Stove” discloses a mechanical structure which is connected to the top of a gas burner having a plurality of gas ports and the cooktop of a stove, wherein an annular curved shield surrounds the burner adjacent the gas ports and extends upwardly and outwardly to the inside edge of the recessed shoulder of the cooktop for directing the heat from the burner toward the grate opening.
U.S. Pat. No. 3,187,742 issued to Power on Jun. 8, 1965 for “Combination Gas Burner Grid And Flame Shield” discloses an improved gas burner grid comprising a substantially rigid and arcuate shield, which is a horizontal plated structure used to eliminate any undesirable overheating of a pan handle.
U.S. Pat. No. 6,851,419 issued to Reiner on Feb. 8, 2005 for “Portable Hiking Stove” discloses an improved portable hiking stove.
U.S. Patent Publication No.: 2005/0115556 issued to Carson et al. on Jun. 2, 2005 for “Turkey Fryer/Outdoor Cooker Wind and Fire Guard” discloses a windscreen device for outdoor grill. The device can be assembled from a horizontal bottom plate and a series of vertical side plates to be a cuboid enclosure or windscreen.
United States Patent Publication No.: 2004/0045542 issued to Zhou et al. on Mar. 11, 2004 is for an “Outdoor Cook Stove”. The Publication discloses a portable outdoor stove including a burner and a wind guard having an opened bottom end of cylinder shape capable of tightly coupled with a cooking vessel, wherein the burner is placed at the center of the opened bottom of the wind guard.
United States Patent Publication No.: 2005/0109330 issued to Pestrue et al. on May 26, 2005 for “Cooking Stove Including Invertible Support Rack, Support Rack With Dual Cooking Surfaces And Method Of Using Same” discloses a stove for outdoor use. The stove includes a hollow shell, supporting structure, and a burner assembly, operatively attached to the side of the shell, and a vessel support rack for placement on the shell.
U.S. Pat. No. 4,850,335 issued to Farnsworth et al. on Jul. 25, 1989 for “Vented Gas Range Top Burner” discloses a top burner for a gas cooking range, which includes a burner vent having a radially upwardly sloping wall to surround the burner head. An annular ring projects upwardly from an inner radial extremity of the wall to direct combustion products from the burner head into immediate scrubbing contact with the bottom of a cooking utensil.
U.S. Pat. No. 6,851,420 issued to Jennings (the Jennings patent) on Feb. 8, 2005 for “Burner With Piloting Ports” discloses an improved burner having ports that are aligned in a defined alignment with respect to an adjacent structure of the a burner body with a piloting zone so that adjacent structure guides the formation of a flame kernel at an outlet of the port.
U.S. Pat. No. 6,093,018 issued to Avshalumov on Jul. 25, 2000 for “Gas Burner” discloses an improved gas burner. The burner comprises in combination means for controlled feeding and subsequent admixing of a secondary air directly to the base of flame in a form of a cap coaxially surrounding a burner head of the gas burner having lateral apertures for issuing combustible air-gas mixture to form a flame.
In addition, gas burners that incorporate two and three flame rings having the laterally oriented gas ports are known in the field of the art. For example, U.S. Pat. No. 6,132,205 issued to Harneit (the Harneit Patent) on Oct. 17, 2000 for “Multi-Ring Sealed Gas Burner” discloses a multi-ring burner assembly that utilizes at least two flame rings to gently and evenly warm food and a third outer flame ring in conjunction with the first two flame rings for cooking food.
The modern gas stoves for the household usage can be classified to a sealed burner mounting and an opened burner mounting (see commercial stoves elsewhere), regarding the mechanical structure for affixing gas burners to the cooktops of the stoves. The former one is also illustrated from U.S. Pat. No. 5,323,759 issued to Hammel et al. on Jun. 28, 1994 for “Sealed Burner Mounting Assembly” (the Hammel patent) and U.S. Pat. No. 6,505,621 issued to Gabelmann on Jan. 14, 2003 for “Sealed Gas Burner Assembly” (the Gabelmann patent).
From the above illustration of the existing technologies on structural components of the cooking stoves, it has been discovered that there is absence of an apparatus in use of regulating transfer of the flame heat from a burner of the gas stove to a utensil in cooking. The apparatus is removably placed on the stove cooktop to surround an upper section of the gas burner and support the utensil. Therefore, heat radiation and convection generated by flame of the gas burner can be well regulated. This means the apparatus focuses heat on the utensil to thereby prevent loss of the heat and increase efficiency of heating the utensil in cooking. For this purpose, U.S. patent application Ser. No. 11/811,521 (the '521 Application) has disclosed such removable flame heat transfer regulating apparatus. The '521 Application further experimentally demonstrates that with the aid of the invented apparatus, it can significantly increase the flame heating efficiency in cooking, when the apparatus is incorporated with an existing stove burner having the laterally oriented gas ports.
However, it would be appreciated that, application of the invented apparatus is only a passive solution in terms of increasing the heating efficiency. This means, what the apparatus can contribute is only to regulate the heat transfer from the flame that is already controlled by structures of the existing burners having the laterally orientated gas ports.
Referring to the Jennings and Harneit Patents, the existing gas burners in the western market provide the laterally oriented gas ports that are generally in the shape of a circular opening or rectangular aperture. They are radially and circumferentially spaced apart on a flame ring, which results in a phenomenon that a mixture of the primary air and combustible gases under the supplied pressure is rushed to flow transversely out of the gas ports. In this situation, the flame kernels generated at the respective outlets of the gas ports also burn in the respective transverse directions. Obviously, this phenomenon is most apparent when the gas ports are provided by the mixture of air and combustible gases at the maximum flow rate (or pressure).
Referring further to FIGS. 2 and 2a of the Jennings patent, there is illustrated that the top flame burns in an ascending direction, when the top flame is in distance to an outlet of a gas port. In this situation, the transverse flow of the mixture of the primary air and combustible gases is sharply weakened due to a quick dissipation of its supplied pressure when the combustible mixture flows out of the outlet of the gas port.
As compared with the naturally upward pattern when a flame burns, the flame pattern governed by the existing gas ports is altered if there is a cooking utensil positioned above the flame, which has been discussed in the '521 Application. In that situation, the flame elongates in the respective transverse directions under the utensil bottom surface. This is because the bottom surface of the utensil blocks the upward pathway of the top flame, which forces the flame positioned under the utensil to transversely extend more before it ends.
In the situation when the maximum flow rate (or pressure) of the combustible mixture is supplied, such flame transverse elongation also reaches the maximum extend. This will cause two major disadvantages even after applying the invented apparatus, which negatively affect the heating efficiency in cooking when applying the most popularly and probably usable cooking utensils which have sizes ranging from 15 cm to 20 cm in diameters.
First, a portion of the heat of the top flame, which is represented by the radiated heat and convected heat, will be escaped through a gap between the bottom of the utensil and top of the apparatus before the heat could reach the utensil. This results in loss of the thermal energies. Such energy loss is absolutely happened since the apparatus having fixed diametrical sizes practically cannot accommodate every specific situations in cooking, including the maximum flow rate of the combustible mixture. In fact, the sizes of the apparatus including a diameter of the top circumference of an inner shell are designed from considering overall effect in application of the apparatus, which includes convenience of usage, ability to fit the respective most popularly and probably usable cooking utensils, and save the thermal energies.
Second, majority of the top flame is moved outwardly to come into contact with areas of the bottom surface of the utensil, wherein the contacted areas are more towards the outer circumference of the utensil bottom surface. This causes a large area of a “cold spot” on the utensil bottom surface. In addition, the flame elongation will further enhance a chilling effect of the flame, if the bottom surface of the utensil is positioned higher than a position that the top flame can reach. The chilling effect is also negative to the object of achieving a high heating efficiency in cooking since the top flame that has the highest temperature cannot directly come into contact with the utensil bottom surface.
Following the above disclosed first reason of losing the thermal energies, it would be appreciated that besides the factor of the transversely oriented gas ports, an additional factor of extra large sizes of the (outer) flame rings is also a cause of losing the thermal energies in cooking even the gas ports of the respective flame rings are oriented upwardly. In the above conclusion, the extra large sizes of the flame rings are defined as that they are not proportional to the diametrical sizes of the respective heat transfer regulating apparatus and the most popularly and probably usable cooking utensils. For example, most burners of the gas stoves in the Asian market including the Chinese market have a dual flame-ring configuration including smaller central and larger outer flame rings. However, the outer rings are usually very large, which the maximum diameters could be 12.5 cm. In that situation, losing the thermal energies absolutely happens in cooking.
Therefore, regarding the above identified two problems, U.S. patent application Ser. No. 12/313,940 (the '940 Application) has disclosed flame (outer) rings having improved gas ports and optimum diametric sizes, which are incorporated with the heat transfer regulating apparatus to best fit the most popularly and probably usable utensils. The improved gas ports have structure for directing the combustible gas-air mixture to flow at an ascending angle relative to a transverse plane where the flame ring is positioned, and securing stabilities of the flame kernels generated at outlets of the respective improved gas ports for prevent lifting or backlash of the kernels.
Obviously changing structures of the gas ports including their orientations and defining the optimum diametrical sizes of the flame rings are the active solutions in terms of increasing the heating efficiency as compared with the passive solution from implementing the heat transfer regulating apparatus disclosed by the '521 Application. Therefore, the '940 Application has brought a better solution for increasing the heating efficiency of the flame in cooking.
Further, the '940 application has additionally disclosed alternative materials of ceramics to be used in manufacturing the apparatus, since the ceramic materials have large heat capacities, which is an additional positive factor to increase the heating efficiency in cooking.
However, the '940 Application does not disclose major structure of an entire stove, including structure related to two subjects. The first one is regarding a preferred embodiment of a lower part of the burner that could additionally contribute to save gases in cooking. The second one is regarding the stove having flat top plates which could conceal the upward apparatus thereby causing the stove to have a flat top surface. Therefore, the stove having the flat top surface can be fitted into a modernized kitchen that requires appliances of ornament and excellent performance. This means a stove is expected to have a few marketable values if its upwardly positioned apparatus is not concealed, since the visual effect of the upwardly positioned apparatus is out of harmony with that of the horizontal surface of the counter top where the stove is installed to thereby not ornament the kitchen.
It would be appreciated that these two subjects are equally important for a marketable stove installed in a kitchen which is the principal place of a house where happens a majority of daily activities of a family.
Gas stoves are popularly used in human society. Usage of the gas stoves consumes tremendous amount of the combustible gases, and also generates significant amount of carbon dioxide gases which are of total greenhouse gases generated by the human society. Therefore, there is a significant need of the present invention to provide a stove, which not only saves combustible gases in cooking but also is ornament, so that the present invention stove could make people enjoy more the modern style of living from reducing the combustible gas consumption to lower the living costs and protect environment, and from improving ornamentation to a modernized kitchen.